The antibacterial effect of fatty acids on Helicobacter pylori infection

Omega-3 and omega-6 polyunsaturated fatty acids and their potential therapeutic role in protozoan infections

Protozoa exert a serious global threat of growing concern to human, and animal, and there is a need for the advancement of novel therapeutic strategies to effectively treat or mitigate the impact of associated diseases. Omega polyunsaturated fatty acids (ω-PUFAs), including Omega-3 (ω-3) and omega-6 (ω-6), are constituents derived from various natural sources, have gained significant attention for their therapeutic role in parasitic infections and a variety of essential structural and regulatory functions in animals and humans. Both ω-3 and ω-6 decrease the growth and survival rate of parasites through metabolized anti-inflammatory mediators, such as lipoxins, resolvins, and protectins, and have both in vivo and in vitro protective effects against various protozoan infections. The ω-PUFAs have been shown to modulate the host immune response by a commonly known mechanism such as (inhibition of arachidonic acid (AA) metabolic process, production of anti-inflammatory mediators, modification of intracellular lipids, and activation of the nuclear receptor), and promotion of a shift towards a more effective immune defense against parasitic invaders by regulation the inflammation like prostaglandins, leukotrienes, thromboxane, are involved in controlling the inflammatory reaction. The immune modulation may involve reducing inflammation, enhancing phagocytosis, and suppressing parasitic virulence factors. The unique properties of ω-PUFAs could prevent protozoan infections, representing an important area of study. This review explores the clinical impact of ω-PUFAs against some protozoan infections, elucidating possible mechanisms of action and supportive therapy for preventing various parasitic infections in humans and animals, such as toxoplasmosis, malaria, coccidiosis, and chagas disease. ω-PUFAs show promise as a therapeutic approach for parasitic infections due to their direct anti-parasitic effects and their ability to modulate the host immune response. Additionally, we discuss current treatment options and suggest perspectives for future studies. This could potentially provide an alternative or supplementary treatment option for these complex global health problems.

Saturated long chain fatty acids as possible natural alternative antibacterial agents: Opportunities and challenges

The spread of new strains of antibiotic-resistant pathogenic microorganisms has led to the urgent need to discover and develop new antimicrobial systems. The antibacterial effects of fatty acids have been well-known and recognized since the first experiments of Robert Koch in 1881, and they are now used in diverse fields. Fatty acids can prevent the growth and directly kill bacteria by insertion into their membrane. For that, a sufficient amount of fatty acid molecules has to be solubilized in water to transfer from the aqueous phase to the cell membrane. Due to conflicting results in the literature and lack of standardization methods, it is very difficult to draw clear conclusions on the antibacterial effect of fatty acids. Most of the current studies link fatty acids' effectiveness against bacteria to their chemical structure, notably the alkyl chain length and the presence of double bonds in their chain. Furthermore, the solubility of fatty acids and their critical aggregation concentration is not only related to their structure, but also influenced by medium conditions (pH, temperature, ionic strength, etc.). There is a possibility that the antibacterial activity of saturated long chain fatty acids (LCFA) may be underestimated due to the lack of water solubility and the use of unsuitable methods to assess their antibacterial activity. Thus, enhancing the solubility of these long chain saturated fatty acids is the main goal before examining their antibacterial properties. To increase their water solubility and thereby improve their antibacterial efficacy, novel alternatives may be considered, including the use of organic positively charged counter-ions instead of the conventional sodium and potassium soaps, the formation of catanionic systems, the mixture with co-surfactants, and solubilization in emulsion systems. This review summarizes the latest findings on fatty acids as antibacterial agents, with a focus on long chain saturated fatty acids. Additionally, it highlights the different ways to improve their water solubility, which may be a crucial factor in increasing their antibacterial efficacy. We finish with a discussion on the challenges, strategies and opportunities for the formulation of LCFAs as antibacterial agents.

Strategies adopted by gastric pathogen Helicobacter pylori for a mature biofilm formation: Antimicrobial peptides as a visionary treatment

Enormous efforts in recent past two decades to eradicate the pathogen that has been prevalent in half of the world's population have been problematic. The biofilm formed by Helicobacter pylori provides resistance towards innate immune cells, various combinatorial antibiotics, and human antimicrobial peptides, despite the fact that these all are potent enough to eradicate it in vitro. Biofilm provides the opportunity to secrete various virulence factors that strengthen the interaction between host and pathogen helping in evading the innate immune system and ultimately leading to persistence. To our knowledge, this review is the first of its kind to explain briefly the journey of H. pylori starting with the chemotaxis, the mechanism for selecting the site for colonization, the stress faced by the pathogen, and various adaptations to evade these stress conditions by forming biofilm and the morphological changes acquired by the pathogen in mature biofilm. Furthermore, we have explained the human GI tract antimicrobial peptides and the reason behind the failure of these AMPs, and how encapsulation of Pexiganan-A(MSI-78A) in a chitosan microsphere increases the efficiency of eradication.

The Activity of Liposomal Linolenic Acid Against Helicobacter pylori In Vitro and Its Impact on Human Fecal Bacteria

Helicobacter pylori (H. pylori) infection is associated with a variety of gastrointestinal diseases. Here, we focused on the activity of a novel nanomedicine-liposomal linolenic acid (LipoLLA) against H. pylori and its impact on human fecal bacteria in vitro. The minimum inhibitory concentrations (MICs) of LipoLLA against 30 H. pylori clinical strains were determined in combination with amoxicillin (AMX), metronidazole (MTZ), levofloxacin (LVFX) and clarithromycin (CAM). Bactericidal activity was measured by generating concentration-bactericidal curves at different times and pH values. Leakage of glucose (GLU) and aspartate aminotransferase (AST) was detected, combined with detection of changes in morphology by electron microscopy, to study the mechanism of action of LipoLLA against H. pylori. The effect of LipoLLA on human fecal bacteria was studied by high-throughput sequencing of fecal samples. We observed a synergistic or additive effect when LipoLLA was combined with AMX, MTZ, LVFX and CAM. The concentration-sterilization curves were pH and time dependent. After treatment with LipoLLA, GLU and AST levels were increased (P<0.05), and the morphology of H. pylori changed significantly. Moreover, LipoLLA activity led to no significant changes in the intestinal flora in terms of alpha diversity, species composition, beta diversity, etc. In conclusion, LipoLLA showed good anti-H. pylori effects. It destroyed the outer membrane barrier and caused leakage of the bacterial contents to achieve anti-H. pylori effects. And LipoLLA had little effect on human fecal bacteria in vitro.

Azithromycin-loaded linolenic acid-modified methoxy poly(ethylene glycol) micelles for bacterial infection treatment

In the study, new polymeric micelles loaded with azithromycin were prepared to enhance azithromycin's solubility and evaluate its in vitro/in vivo antibacterial activity against Staphylococcus aureus. Amphiphilic α-Linolenic acid-methoxy poly (ethylene glycol) polymer (MPEG-LNA) was synthesized through DCC-DMAP esterification procedure. Through thin-film hydration method, optimized azithromycin-loaded micelles (AZI-M) were prepared with 87.15% of encapsulation efficiency and 11.07% of drug loading capacity when the ratio of LNA to MPEG was 4. Azithromycin's water-solubility was obviously enhanced due to its loading into the polymeric micelles. The azithromycin-loaded micelles were characterized in terms of x-ray diffraction, Fourier transform infrared spectroscopy, in vitro release, and in vitro/in vivo antibacterial experiments. Although the drug-loaded micelles provided a slow and continuous azithromycin's release in comparison with free azithromycin, in vitro antibacterial activity results confirmed that its effect on the inhibition of bacterial growth and biofilm formation was similar to free azithromycin. It is more interesting that the azithromycin-loaded micelles achieved good in vivo antibacterial therapeutic effect like QiXian® (azithromycin lactobionate injection) in mouse model of intraperitoneal infection. AZI-M can be considered as a potential candidate for in vivo antibiotic therapy of Staphylococcus aureus infections.

Targeting and Killing the Ever-Challenging Ulcer Bug

TreatingHelicobacter pylori(H. pylori) infections has been a never-ending challenge, which has contributed to the high incidence of gastric cancer. The antibiotics commonly used are not reaching the infection site in its active state and in a concentration high enough to effectively kill the bacteria. In this context, amoxicillin-loaded lipid nanoparticles with carefully chosen materials were developed, namely dioleoylphosphatidylethanolamine (DOPE) as a targeting agent and Tween®80 and linolenic acid as antimicrobial agents. This work shows the ability of these nanoparticles in (i) targeting the bacteria (imaging flow cytometry) and inhibiting their adhesion to MKN-74 cells (bacteria-gastric cells adhesion model); (ii) killing the bacteria even as an antibiotic-free strategy (time-kill kineticstudies, scanning electron microscopy, and bacterial membrane permeability studies); (iii)overcoming gastrointestinal features using a newly developedin vitroinfection model that includes both physical (epithelial cells and mucus) and the chemical (acid medium) barriers; and in (iv) being incorporated in a floating system that can increase the retention time at the stomach. Overall, this work presents an effective nanosystem to deal with the ulcer-bug. Besides, it also provides two innovative tools transferable to other fields-anin vitroinfection model and a floating system to incorporate nanoparticles.

Eight different bioactivity profiles of 40 cinnamons by multi-imaging planar chromatography hyphenated with effect-directed assays and high-resolution mass spectrometry

Spices contain plenty of bioactive compounds, used to valorize foods. However, product quality may be affected by contaminations and adulterations along the global production chain. A newly developed multi-imaging in combination with bioactivity screening directly pointed to individual multi-potent compounds. For cinnamon as prominent example, the multi-imaging results provided a wealth of new information on their effects and clearly visualized the valorizing potential of cinnamon to foods. The separation focus was in the mid-polar to apolar range. Eight effect-directed assays (EDA, i.e. one radical scavenging, two biological and five biochemical assays) were performed in situ the high-performance thin-layer chromatography (HPTLC) adsorbent. Several multi-potent compound zones were revealed and further characterized by high-resolution mass spectrometry (HRMS), highlighting the bioactive potential of cinnamaldehyde, cinnamic acid, benzoic acid, coumarin, linoleic acid, oleic acid, stearic acid, palmitic acid, caproic acid, and linalool oxide. This HPTLC-UV/Vis/FLD-EDA-HRMS profiling provided comprehensive information on product quality and safety.

Beyond cardiovascular medicine: potential future uses of icosapent ethyl

The REDUCE-IT trial demonstrated that icosapent ethyl, an ethyl ester of eicosapentaenoic acid (EPA), reduced cardiovascular events in an at-risk population by a substantial degree. While the cardiovascular protective properties of this compound are now proven, several other potential uses are being actively explored in clinical studies. These areas of investigation include cancer, inflammatory bowel disease, infections, Alzheimer's disease, dementia, and depression. The next decade promises to deepen our understanding of the beneficial effects that EPA may offer beyond cardiovascular risk reduction.

Effects of Multi-Strain Probiotics on Immune Responses and Metabolic Balance in Helicobacter pylori-Infected Mice

Chronic inflammation caused by Helicobacter pylori infection increases the risk of developing gastric cancer. Even though the prevalence of H. pylori infection has been decreased in many regions, the development of antibiotic resistance strains has increased the difficulty of eradicating H. pylori. Therefore, exploring alternative approaches to combat H. pylori infection is required. It is well-known that probiotic therapy can improve H. pylori clearance. In this study, H. pylori-infected mice were treated with Lactobacillus fermentum P2 (P2), L. casei L21 (L21), L. rhamnosus JB3 (JB3), or a mixture including the aforementioned three (multi-LAB) for three days. All the lactic acid producing bacteria (LAB) treatments decreased H. pylori loads in the stomach and vacA gene expression, H. pylori specific immunoglobulin (Ig) A, and IgM levels in stomach homogenates, as well as serum levels of interferon-gamma and interleukin-1 beta. The multi-LAB and JB3 treatments further restored the superoxide dismutase and catalase activities suppressed by H. pylori infection. Furthermore, H. pylori infection decreased serum concentrations of 15 kinds of amino acids as well as palmitic acid. The multi-LAB treatment was able to recover the serum levels of alanine, arginine, aspartate, glycine, and tryptophan, which are all important in modulating immune functions. In addition, butyric acid, valeric acid, palmitic acid, palmitoleic acid, stearic acid, and oleic acid levels were increased. In this study, multi-LAB revealed its ability to adjust the composition of metabolites to improve health. To date, the mechanisms underlying how LAB strains crosstalk with the host are not fully understood. Identifying the mechanisms which are regulated by LABs will facilitate the development of effective therapies for infection in the future.

Omega polyunsaturated fatty acids and parasitic infections: An overview

Omega-3 and omega-6 polyunsaturated fatty acids are synthesized from the essential fatty acids alpha-linolenic acid and linoleic acid, respectively. They are pivotal components of all mammalian cells and were found to be useful in prevention and treatment of a variety of health problems owing to their anti-inflammatory and anti-microbial properties. Omega-3 and omega-6 polyunsaturated fatty acids are further metabolized to anti-inflammatory mediators, such as lipoxins, resolvins, and protectins. Moreover, these polyunsaturated fatty acids were found to have in vivo and in vitro protective efficacies against some parasitic infections. Therefore, dietary intake of polyunsaturated fatty acids should be encouraged because of their considerable beneficial effects.

Eradication of Helicobacter pylori: the power of nanosized formulations

Helicobacter pylori is a pathogen that is considered to cause several gastric disorders such as chronic gastritis, peptic ulcer and even gastric carcinoma. The current therapeutic regimens mainly constitute of a combination of several antimicrobial agents and proton pump inhibitors. However, the prevalence of antibiotic resistance has been significantly lowering the cure rates over the years. Nanocarriers possess unique strengths in this regard owing to the fact that they can protect the drugs (such as antibiotics) from the harsh environment in the stomach, penetrate the mucosal barrier and deliver drugs to the desired site. In this review we summarized recent studies of different antibacterial agents orally delivered by nanosized carriers for the eradication of H. pylori.

Effectiveness of omega-3 polyunsaturated fatty acids against microbial pathogens

Microorganisms provide both beneficial and harmful effects to human beings. Beneficial effects come from the symbiotic relationship that exists between humans and microbiota, but then several human illnesses have turned some friendly microbes into opportunistic pathogens, causing several microbial-related diseases. Various efforts have been made to create and utilize antimicrobial agents in the treatment and prevention of these infections, but such efforts have been hampered by the emergence of antimicrobial resistance. Despite extensive studies on drug discovery to alleviate this problem, issues with the toxicity and tolerance of certain compounds and continuous microbial evolution have forced researchers to focus on screening various phytochemical dietary compounds for antimicrobial activity. Linolenic acid and its derivatives (eicosapentaenoic acid and docosahexaenoic acid) are omega-3 fatty acids that have been studied due to their role in human health, being important for the brain, the eye, the cardiovascular system, and general human growth. However, their utilization as antimicrobial agents has not been widely appreciated, perhaps due to a lack of understanding of antimicrobial mechanisms, toxicity, and route of administration. Therefore, this review focuses on the efficacy, mechanism, and toxicity of omega-3 fatty acids as alternative therapeutic agents for treating and preventing diseases associated with pathogenic microorganisms.

Antibacterial Free Fatty Acids and Monoglycerides: Biological Activities, Experimental Testing, and Therapeutic Applications

Antimicrobial lipids such as fatty acids and monoglycerides are promising antibacterial agents that destabilize bacterial cell membranes, causing a wide range of direct and indirect inhibitory effects. The goal of this review is to introduce the latest experimental approaches for characterizing how antimicrobial lipids destabilize phospholipid membranes within the broader scope of introducing current knowledge about the biological activities of antimicrobial lipids, testing strategies, and applications for treating bacterial infections. To this end, a general background on antimicrobial lipids, including structural classification, is provided along with a detailed description of their targeting spectrum and currently understood antibacterial mechanisms. Building on this knowledge, different experimental approaches to characterize antimicrobial lipids are presented, including cell-based biological and model membrane-based biophysical measurement techniques. Particular emphasis is placed on drawing out how biological and biophysical approaches complement one another and can yield mechanistic insights into how the physicochemical properties of antimicrobial lipids influence molecular self-assembly and concentration-dependent interactions with model phospholipid and bacterial cell membranes. Examples of possible therapeutic applications are briefly introduced to highlight the potential significance of antimicrobial lipids for human health and medicine, and to motivate the importance of employing orthogonal measurement strategies to characterize the activity profile of antimicrobial lipids.

Antibacterial Free Fatty Acids and Monoglycerides: Biological Activities, Experimental Testing, and Therapeutic Applications

Antimicrobial lipids such as fatty acids and monoglycerides are promising antibacterial agents that destabilize bacterial cell membranes, causing a wide range of direct and indirect inhibitory effects. The goal of this review is to introduce the latest experimental approaches for characterizing how antimicrobial lipids destabilize phospholipid membranes within the broader scope of introducing current knowledge about the biological activities of antimicrobial lipids, testing strategies, and applications for treating bacterial infections. To this end, a general background on antimicrobial lipids, including structural classification, is provided along with a detailed description of their targeting spectrum and currently understood antibacterial mechanisms. Building on this knowledge, different experimental approaches to characterize antimicrobial lipids are presented, including cell-based biological and model membrane-based biophysical measurement techniques. Particular emphasis is placed on drawing out how biological and biophysical approaches complement one another and can yield mechanistic insights into how the physicochemical properties of antimicrobial lipids influence molecular self-assembly and concentration-dependent interactions with model phospholipid and bacterial cell membranes. Examples of possible therapeutic applications are briefly introduced to highlight the potential significance of antimicrobial lipids for human health and medicine, and to motivate the importance of employing orthogonal measurement strategies to characterize the activity profile of antimicrobial lipids.

A proposed role for diffusible signal factors in the biofilm formation and morphological transformation of Helicobacter pylori

Due to the increasing resistance of Helicobacter pylori to antibiotics, there is a growing need for new strategies for the effective eradication of this pathogen. The inhibition of quorum-sensing activity in most microorganisms leads to a decrease in virulence. A different reaction is observed in H. pylori, as interfering with the production of autoinducer-2 initiates biofilm formation and increases the survival of these bacteria. Therefore, it is believed that there is an alternative way to control the physiological changes of H. pylori exposed to environmental stress. In this article, we present the compounds probably involved in the modulation of H. pylori virulence. Diffusible signal factors (DSFs) are fatty acid signal molecules involved in communication between microbes. DSFs are likely to stimulate H. Pylori transition into a sedentary state that correlates with bacterial transformation into a more resistant coccoid form and initiates biofilm formation. Biofilm is a structure that plays a crucial role in protecting against adverse environmental factors (low pH, oxidative stress, action of immune system) and limiting the effective concentration of antimicrobial substances. This article has suggested and characterized the existence of an alternative DSF-mediated cell-cell signaling of H. pylori, which controls autoaggregative behaviors, biofilm formation, and the transition of microorganisms into the coccoid form.

Pathogenesis of Helicobacter pylori infection

Helicobacter pylori is estimated to infect more than half of the worlds human population and represents a major risk factor for chronic gastritis, peptic ulcer disease, MALT lymphoma, and gastric adenocarcinoma. H. pylori infection and clinical consequences are controlled by highly complex interactions between the host, colonizing bacteria, and environmental parameters. Important bacterial determinants linked with gastric disease development include the cag pathogenicity island encoding a type IV secretion system (T4SS), the translocated effector protein CagA, vacuolating cytotoxin VacA, adhesin BabA, urease, serine protease HtrA, secreted outer membrane vesicles, and many others. The high quantity of these factors and allelic changes in the corresponding genes reveals a sophisticated picture and problems in evaluating the impact of each distinct component. Extensive work has been performed to pinpoint molecular processes related to H. pylori-triggered pathogenesis using Mongolian gerbils, mice, primary tissues, as well as novel in vitro model systems such as gastroids. The manipulation of host signaling cascades by the bacterium appears to be crucial for inducing pathogenic downstream activities and gastric disease progression. Here, we review the most recent advances in this important research area.

Mucosal Interactions between Genetics, Diet, and Microbiome in Inflammatory Bowel Disease

Numerous reviews have discussed gut microbiota composition changes during inflammatory bowel diseases (IBD), particularly Crohn’s disease (CD). However, most studies address the observed effects by focusing on studying the univariate connection between disease and dietary-induced alterations to gut microbiota composition. The possibility that these effects may reflect a number of other interconnected (i.e., pantropic) mechanisms, activated in parallel, particularly concerning various bacterial metabolites, is in the process of being elucidated. Progress seems, however, hampered by various difficult-to-study factors interacting at the mucosal level. Here, we highlight some of such factors that merit consideration, namely: (1) the contribution of host genetics and diet in altering gut microbiome, and in turn, the crosstalk among secondary metabolic pathways; (2) the interdependence between the amount of dietary fat, the fatty acid composition, the effects of timing and route of administration on gut microbiota community, and the impact of microbiota-derived fatty acids; (3) the effect of diet on bile acid composition, and the modulator role of bile acids on the gut microbiota; (4) the impact of endogenous and exogenous intestinal micronutrients and metabolites; and (5) the need to consider food associated toxins and chemicals, which can introduce confounding immune modulating elements (e.g., antioxidant and phytochemicals in oils and proteins). These concepts, which are not mutually exclusive, are herein illustrated paying special emphasis on physiologically inter-related processes.

PREVALENCE OF HELICOBACTER PYLORI TEN YEARS AGO COMPARED TO THE CURRENT PREVALENCE IN PATIENTS UNDERGOING UPPER ENDOSCOPY

Background

Helicobacter pylori has been extensively studied since 1982 it is estimated that 50% of the world population is affected. The literature lacks studies that show the change of its prevalence in the same population over time.

Aim

To compare the prevalence of H. pylori in 10 years interval in a population that was submitted to upper endoscopy in the same endoscopy service.

Method

Observational, retrospective and cross-sectional study comparing the prevalence of H. pylori in two samples with 10 years apart (2004 and 2014) who underwent endoscopy with biopsy and urease. Patients were studied in three consecutive months of 2004, compared to three consecutive months of 2014. The total number of patients was 2536, and 1406 in 2004 and 1130 in 2014.

Results

There were positive for H. pylori in 17 % of the sample as a whole. There was a significant decrease in the prevalence from 19.3% in 2004 to 14.1% in 2014 (p<0.005).

Conclusion

There was a 5.2% reduction in the prevalence of H. pylori comparing two periods of three consecutive months with 10 years apart in two equivalent population samples.